MXPA99010448A - Cutting insert for shaping by chipping - Google Patents

Abstract

The invention relates to a cutting insert for shaping metallic workpieces by chipping. Said cutting insert is especially suited for use in solid drills or double-bit cutters. It has at least one cutting edge (12) which is delimited by a chipping face (14) and a flank (16) and extends between two cutting corners (10). Said cutting edge comprises two sections (20) of the cutting edge which form an obtuse angle and in the area of a roof-shaped tip (18) merge into each other. The chipping face (14) has a raised shaped chipping element which extends from the inside of the chipping face (14) as far as the cutting edge (12), from where it reaches beyond the roof-shaped tip (18) partially across the two sections (20) of the cutting edge. Said cutting edge sections (20) and the adjoining chipping faces (14) comprise a step (24) delimiting the shaped chipping element (22), the edges (26) of which step serve as additional cutting edges of the shaped chipping element (22).

Description

CUTTING INSERT FOR CONFIGURATION BY REMOVING Description The invention relates to a cutting insert for configuration by grinding, preferably of metal tools with at least one cutting edge that extends between two cutting corners and define on one face and a grinding side, whose cutting edge has two sections of the cutting edge. partially active cutting edge forming an obtuse angle where they join together in the area of a dome-shaped tip. Thus, the roughing face has at least one roughing element configured in relief. The cutting inserts with said shaped grinding elements are known, for example from DE-A-44 22 312. The end of grinding elements in said reference is in front of the cutting edge and extend wedge-shaped in the direction of the cutting edge. cutting edge. The grinding elements configured in relief also achieve the separation of the cylindrical wedge at certain points through a deliberate inclusion of energy so that the stable cross section of the cylindrical wedge is weakened and the energy action is reduced. enters the cylindrical wedge in the cutting insert. Also the characteristics of the roughing of the cutting insert leave much to be desired, particularly during the beginning of the drilling.

Starting from this, the basic purpose of the invention is to provide a cutting insert for shaping configuration, of the type described above, which are distinguished through particularly favorable characteristics during the beginning of the perforation by the formation of structured cylindrical wedge and through a silent bruising. To achieve this purpose, the characteristic combination described in claim 1 of the patent is suggested. The advantageous embodiments and developments of the invention result from the dependent claims. The basic idea of the invention is that through a splitting of the cutting edge in the driving and pulling cutting edge portions, a smooth drilling start and a life-size stable hole drilling operation without lateral deflection is achieved. of the respective tool. To achieve this, it is suggested, according to the invention, that the roughing element formed in relief extends from the inside of the cutting face to the cutting edge, and therefore, extending to form the tip in the form of a vault partially over the two sections of the cutting edge. A particularly favorable guiding behavior on the total drilling operation is achieved when the edge sections and the adjacent roughing face portions have a step defining the shaped grinding member, and when the cutting edge sections preferably extend continuously in ascending form from the lower edge of the step to the cutting corner. The cutting edge sections advantageously reach, in their extension towards the cutting corners, essentially the level of the cutting edges in the area of the shaped roughing element. It has proven to be particularly advantageous when the step of the edges extending over the grinding face forms an angle of 90 ° to 110 ° with the section of the cutting edge associated on its side face with the respective cutting corner, and therefore it functions as the independent additional edges of the configured roughing element. In order to achieve a division of the circular wedges in the area of the configured grinding step, it may be advantageous when the step surfaces defining the additional cutting edges form an acute angle of 75 ° C to 88 ° C with the portions of the face of roughing adjacent fronts. The main and additional cutting edges of the cutting operation element, whose edges lead during the cutting operation, due to their support function, they result in a better guide behavior and create a vibration reduction in particular in the scale of higher vibrations with high frequencies and, therefore, reduce the creation of noise. In order to improve the guiding behavior without a division of circular wedges in the area of the shaped roughing element, it is advantageous when the step surfaces defining the additional cutting edges form an obtuse angle of 70 ° C to 88 °, preferably from 75 ° to 85 °, with the portions of the front roughing face in adjacent form. It has proven to be particularly advantageous for this purpose when the length of the cutting edge in the area of the shaped roughing element is 15% to 40% of the total length of the cutting edge. To improve the force balance during the cutting operation, it is possible to design the cutting element also asymmetrically configured with respect to the dome-shaped tip. In particular, it is possible for this purpose that the driven cutting edges and the roughing face portions extend toward a cutting corner and inclined towards the other cutting corner. In order to improve the guiding behavior of a drilling tool equipped with the cutting elements of the invention, in particular during the beginning of the drilling, it is suggested, according to a preferred embodiment of the invention, that the equation be applied h = a - f / tan gives the height of the step of the configured grinding element, where f is the tool fed by rotation of the machining tool, d is the free angle in the driving area of the cutting edge portion, it is already a factor = 0.2 to 1.5, preferably from 0.3 to 0.8. In order to improve the formation of circular wedges and the removal of circular wedges, the grinding faces extend concavely in the area of the configured grinding element and the outside of the grinding element configured of each of the cutting edge falling initially and then ascending to a remote platform at the edge. A further improvement in this respect is achieved by the roughing angle continuously decreasing from the edges of the step of the formed grinding element towards the cutting corner. The cutting inserts of the invention are preferably used in solid drills or in double cutters with at least two cutting inserts. The invention will be described in greater detail hereinafter in connection with an illustrative embodiment shown schematically in the drawings, in which: Figure 1 is a diagrammatic illustration of a cutting insert for setting by grinding; Figure 2 is a side view of the cutting insert in the direction of the side; Figure 3 is a bottom view of the cutting insert in the direction of the roughing face; Figure 4a illustrates an elongated cut of Figure 3 in the area of the shaped roughing element; Figure 4b is a cross-sectional view along the intersecting line IV-IV of Figure 3; and Figures 5a and 5b, illustrate an improved exemplary embodiment of a cutting insert according to Figures 2 and 3.

The cutting insert illustrated in the drawings is primarily designed for drilling tools, such as solid drills or double cut drills. It is designed as a rotary insert with a hexagonal contour, the three cutting edges 12 of which - the cutting edges are connected to each other in the cutting corners 10 defining an acute angle a, are defined by a roughing face 14 and a side 16 , and each has two edge sections 20 fusing together, while forming an obtuse angle ß in the area of a dome-shaped tip 18. Depending on the manner in which the rotating insert is fixed, one of the cutting edges it is activated with the associated cutting edge sections 20. The roughing face 14 is associated with each cutting edge 12 having a relief shaped contouring element extending from the inside of the roughing face 14 to the respective cutting edge 12, and extends beyond the two sections of the cutting edge 20 to define the dome-shaped tip 18. The cutting edge sections 20 and the adjacent roughing face portions 1 4 have a step 24 which limits the shaped grinding element 22, the edges 26 of which an angle is formed? > 90 ° with the respective cutting edge section on its side faces of the respective cutting corners 10, and forming an additional front cutting edge, which is part of the cutting cutting edge 12 'in the area of the shaped grinding element 22. length of the driving cutting edge 12 'in the area of the shaped roughing element 22 is, in the illustrative embodiment shown, about 25% of the total cutting edge length, while the height h of the step 24 of the shaped roughing element 22 it is determined according to the equation h = af / tan d, where f is the tool fed by rotation (figure 4a), d is the free angle in the area of the portion of the driving cutting edge 12 '(Figure 4b) and the factor a is approximately 0.4 in the illustrative embodiment shown in Figure 4a. The feeding direction is indicated by the arrow 25 in Figure 4a, while the dotted lines 1, 2, 3, 4, 5 and 6, which are perpendicular with respect to the feeding direction 25, indicate the position of the cutting insert. , each being one tenth of a rotational step (0.1 f) within the tool. Figure 4a shows that the bisector angle 29 of the dome-shaped tip 18 forms an acute angle e with the feed direction 25. Therefore, an exchange that depends on the time of the engagement points of the edge sections results cutting that may vary during the beginning of the drilling, depending on the angle e. It is important that when the end of the cutting cutting edge 12 'is reached, a certain period of time passes until the pulling sections 12"of the cutting edge engage, this delay summing, in the illustrative embodiment shown, approximately half rotation of the respective tool The formed roughing element 22 during the average rotation pierces a channel in the tool, which acts to center and stabilize the traction cutting edge sections 12"having a continuously increased shape from the lower edge of the tool. step 24 towards the cutting corner 10 and an angle of attack decreasing continuously along said extension. The cutting edges 12 are partially beveled (bevel 32) in the area of the cutting corners 10, depending on the direction of rotation of the tool. The roughing faces 14, both in the area of the shaped roughing element 22, and in the area between the step 24 and the cutting corners 20, have a concave shape, which initially falls from the cutting edge 12 ', 12"and then ascends to a remote platform 28 the edge (compare Figure 2). An opening 30 exists in the center of the platform 28 for penetration by a fastening screw not shown. The illustrative embodiment according to Figures 5a and 5b differs from one shown in Figures 2 and 3 in that the configured roughing element 22 is arranged asymmetrically with respect to the tip of the dome 18 and extends with a reduced inclination to a cutting corner (right) 10 and with an increased slope to the other cutting corner (left) 10. This measurement makes it possible to achievemy. , with the cutting elements overlapping with each other in the tool, a balance of radial force during the drilling operation, in particular, during the drilling operation. Figure 5a further shows that the additional cutting edge 26 of the shaped roughing element is undercut in the area of the step 24 with a cutting angle p. It is possible that this structure could cause a favorable circular wedge shape for the removal of burrs and the division into the curved wedges. In conclusion, the following is stated: the invention relates to a cutting insert for the configuration by grinding of metal tools. The cutting insert is mainly suitable for use in solid drills or double wedge cutters. It has at least one cutting edge 12 extending between two cutting corners 10 and formed by a grinding face 14 and a side 16, whose cutting edge 12 has two sections of at least partially cutting edges 20, which define a obtuse angle as they join with one another in the area of a dome-shaped tip 18. A roughing element configured in relief is provided on the roughing face, whose element extends from the inside of the roughing face 14 to the cutting edge 12 and extending towards the two sections of the cutting edge 20 to define the dome-shaped tip 18. The sections of the cutting edge 20 and the adjacent roughing faces 14 have a step that limits the shaped roughing element 22, the edges 26 of which the step functions as the additional cutting edges of the shaped roughing element 22.

Claims (17)

1. CLAIMS 1. A cutting insert for configuration by grinding preferably metal tools with at least one cutting edge (12) extending between two cutting corners (10) and defined on a roughing face (14) and a side (16) ), whose cutting edge (12) has at least two partially active cutting edge sections (20), which form an obtuse angle (ß) and which join with one another in the dome-shaped area of the tip ( 18), so that the roughing face (14) having a roughing element configured in relief (22), extending from the inside of the roughing face (14) to the cutting edge (12) and extending partially over the two sections of the cutting edge (20) forming a point in the shape of a vault (18). The cutting insert according to claim 1, characterized in that the cutting edge sections (20) and the adjacent grinding face portions (14) have a step (24) defining the configured grinding element (22). 3. The cutting insert according to claim 2, characterized in that the driving portions (12") of the cutting edges (12), whose portions are provided on the outside of the shaped grinding element (22), are continuously extended preferably in a form ascending from the lower edge of the respective step (24) to the adjacent cutting corner (10). 4. The cutting insert according to claim 3, characterized in that the driving portions (12 ') of the cutting edges (12) reach their extension towards the cutting corners (10) essentially the level of the driving portions (12') of the cutting edges (12), whose conductive portions are provided inside the configured roughing element (22). The cutting insert according to one of claims 1 to 4, characterized in that the edges of the step (24) extend over the roughing face (14) forming an angle (?) Of 80 ° to 120 °, preferably from 95 ° to 105 °, with the associated cutting edge section (20) on the side facing the respective cutting corner (10). The cutting insert according to one of claims 1 to 5, characterized in that the roughing face (14) extends concavely in the area of the shaped roughing element (22) from the portion of the conducting cutting edge (12 ') declining initially and then ascending to a remote platform (28) of the edge. The cutting insert according to one of claims 1 to 6, characterized in that the grinding face (14) extends concavely in the area between the step (24) and the adjacent cutting edge (10) from the cutting edge portion (12") initially falling and then forming the step partially upwardly to the remote platform from the edge. 8. The cutting insert according to one of claims 1 to 7, characterized in that the roughing angle of the cutting edge portion (12") decreases continuously from the step (24) towards the adjacent cutting edge (10). The cutting insert according to one of claims 5 to 8, characterized in that the edges (26) of the steps (24) are designed as additional cutting edges of the shaped grinding element (22). with one of the claims 1 to 9, characterized in that the length of the driving cutting edge (12 ') is 15 to 50% of the total length of the cutting edge (12) in the area of the shaped grinding element (22). The cutting insert according to one of claims 1 to 10, characterized in that the shaped grinding element (22) is designed asymmetrically with respect to the dome-shaped tip (18) 12. The cutting insert according to in one of claims 1 to 11, characterized in that the cutting edge portion of the pipe (12 ') extends dropping inclinedly towards a cutting corner (10) and in ascending shape inclined towards the other cutting corner (10). The cutting insert according to one of claims 9 to 12, characterized in that the step of surfaces (24) limit the additional cutting edges forming an acute angle (p) from 75 ° to 88 °, preferably from 79 ° to 84 °, with the adjacent conductive cutting face portions (14) . The cutting insert according to one of claims 9 to 12, characterized in that the step of surfaces (24) limits the additional cutting edges (24) forming an obtuse angle (p) of 92 ° to 110 °, preferably from 95 ° to 105 °, with the grinding face portions being adjacent (14). The cutting insert according to one of claims 1 to 10, with several cutting edges (12), which preferably delimit a polygon designed as a triangle and each consisting of two edge sections (20), characterized in that cutting corners (10) are provided between the individual cutting edges (1) at least partially bevelled. 16. A machining tool with a cutting insert according to one of claims 1 to 15, whereby the tool is changed (arrow 25) and rotated in relation to a tool during the operation of machinery, characterized in that the equation h = af / tan d is applied to the height of the step (h) of the configured grinding element (22), so f is the tool fed by rotation, and d is the free angle in the area of the edge portion of driving cut (12 ') and the factor a is = 0.2 to 1.5, preferably from 0.3 to 0.8. 17. A machine tool according to claim 16, characterized in that it is designed as a solid drilling machine or as a double wedge cutter with at least two cutting inserts according to one of claims 1 to 15.